1. Field of the Invention
The present invention relates generally to power transmission apparatuses for wind power generation and wind power generators using the same and, more particularly, to a power transmission apparatus for wind power generation and a wind power generator using the power transmission apparatus, which is constructed such that when an impeller is rotated by wind at an initial stage, sufficient initial driving force can be applied to the impeller, so that despite the wind blowing weakly, the operation of the impeller and generating unit can easily begin. The power transmission apparatus is operated in such a way that the rotating force of the impeller is transmitted to the generating unit by a magnetic repulsive force or mechanism using power transmission springs, so that friction between parts pertaining to power transmission is prevented and the parts are prevented from becoming worn thus preventing noise and increasing the lifetime of the wind power generator, and so that a problem of an offset between shafts of the two parts pertaining to power transmission can be solved, thus fundamentally preventing malfunctioning during power transmission, thereby enhancing the efficiency of the wind power generator.
2. Description of the Related Art
Recently, on residential streets, installation of wind power generators, which have impellers to be rotated by wind and illuminators such as LEDs or the like, has increased. In such a wind power generator, an impeller is rotated by the kinetic energy of wind. The rotating force of the impeller rotates a rotor and a rotor shaft of a generating unit, which is installed in the generator body, using a power transmission apparatus including gears or the like, thus generating electricity. An illuminator, such as an LED, is turned on by the generated electricity.
Meanwhile, the wind power generator which operates the LED or the like using the mechanical energy of the impeller that is rotated by wind power may be used not only on residential streets but also in various other locations such as farms, pastures, the coast, etc.
However, in the conventional techniques, because the rotating force of the impeller is transmitted to the generating unit using the gear mechanism, a relatively large initial driving force is required. Therefore, the impeller may not be rotated by relatively weak wind, with the result that the LED is not turned on.
In other words, because the conventional techniques are constructed such that a drive gear coupled to the impeller is in surface contact with a driven gear coupled to a rotor shaft of the generating unit, the magnitude of initial driving force required for rotating the impeller at an initial stage is increased. Thus, if relatively weak wind blows, the impeller may not be smoothly rotated, because sufficient initial driving force cannot be obtained. Thereby, power generation becomes unsatisfactory. Moreover, in the case where the capacity of the rotor is relatively large, the size of the gears is also increased, so that it is very difficult to rotate the impeller using low wind power. As such, in the case where the impeller is not satisfactorily rotated, the operation of the generating unit is also unsatisfactory, with the result that the LED cannot be turned on even when necessary. That is, the reliability of the wind power generator is deteriorated. In particular, in an overpopulated city where wind is comparatively weak, it is more difficult to rotate the impeller using wind power.
As stated above, in the case where the rotating force of the impeller is transmitted to the generating unit using the gear mechanism, friction between gears is relatively large, thus resulting in an increase of a required magnitude of the initial driving force. Hence, when weak wind is blowing or in the case where the capacity of the rotor is relatively large, the impeller may not rotate smoothly. As a result, the wind power generator may not be operated even when necessary, that is, it may be useless.
Furthermore, in the conventional technique, every when the impeller rotates, friction between the parts that pertain to power transmission occurs, causing abrasion of the parts and severe noise. The abrasion of the parts pertaining to power transmission reduces the lifespan of the wind power generator.
In addition, if an offset phenomenon occurs, in which the power transmission axes of the impeller and the generating unit become misaligned because of some cause or other, the efficiency of transmitting the rotating force of the impeller to the generating unit is greatly reduced. Hence, the LED may not be satisfactorily operated. Furthermore, the offset phenomenon of the power transmission axes further increases a required magnitude of the initial driving force of the wind power generator, so that the impeller cannot rotate smoothly.
As well, in the conventional techniques using the gear mechanism, a backlash event is induced, causing momentary impact. The momentary impact is applied to critical parts of the wind power generator, thus reducing the durability thereof, and causing various other problems.
Moreover, lubricating oil may be periodically supplied into a gear box. Therefore, the maintenance of the wind power generator is inconvenient and difficult. Due to the gears, lots of noise and vibration occur.
In addition, in the daytime, due to the solar heat and frictional heat in the gear box, oil in the gear box evaporates or is exhausted by being consumed naturally. Hence, the maintenance of the wind power generator is more difficult. As well, there may be problems attributable to the loosening of bolts or screws for assembly of the critical parts. Particularly, in the case of a wind power generator having a large capacity, the operation of charging lubricating oil into a gear box is more and more inconvenient and difficult, and greater noise and vibration occur.